下载的源代码，都没动。php是5.6.25版本的

Warning: mysqli_connect(): (HY000/1045): Access denied for user 'root'@'localhost' (using password: YES) in C:\wamp\www\mvc\framework\libs\db\mysql.class.php on line 25

Warning: mysqli_error() expects exactly 1 parameter, 0 given in C:\wamp\www\mvc\framework\libs\db\mysql.class.php on line 26